A photocoupler is a component that transfers electrical signals in the form of light between two isolated circuits. A conventional photocoupler generally includes two conductive frames, a light-sensing element provided on an upper surface of one conductive frame, and a light emitting element provided on a lower surface of the other conductive frame. The light emitting element is driven by an input electric signal to convert the input electric signal to a light signal, and the light-sensing element is for receiving the light signal and then outputting an electric signal converted from the light signal.
The photocoupler has been widely used in various electrical products. However, the electrical characteristics of the conventional photocoupler is unable to meet the required standard when the electrical characteristics of the photocoupler are affected due to a distance being too close between the two conductive frames, or an overlapping area being too large between the two conductive frames which will cause a large capacitance value and a low CMRR (Common Mode Rejection Ratio).